Despite the tremendous inter-individual variability in the response to environmental toxins, we simply do not understand why certain people develop disease when challenged with environmental agents and others remain healthy. Although an emerging consensus suggests that many of the complex and prevalent diseases that humans develop occur as a result of multiple biologically unique gene-gene and gene-environment interactions, this conceptual framework is limited. Environmental exposures affect those that are vulnerable temporally (age), spatially (geographically), and by unique circumstance (co-morbid disease, nutritional status, economic status, race, and genetics). Even this paradigm fails to address the complex interaction of endogenous and exogenous risks that ultimately cause disease. While the recent advances in human and molecular genetics provide an unparalleled opportunity to understand how genes interact with environmental stimuli to either preserve health or cause disease, without accounting for the temporal, spatial, and other unique components of an individual's microenvironment, our understanding of environmental health will remain incomplete. Thus, the theme of our proposed Center is to understand how biological, physiological, and social aspects of vulnerability alter the effect of environmental toxins on human health. Specific goals of the Center are: 1. To develop and operate an interdisciplinary environmental health sciences research center with a focus on understanding how biological, physiological, and social aspects of vulnerability alter the effect of environmental toxins on human health; 2. To enhance research in environmental health at Duke by promoting research interactions between existing interdisciplinary programs in environmental health, fostering the development of new research loci in environmental health, and establishing an infrastructure to support and extend research in environmental health; 3. To identify new and creative policy approaches that combine advanced understanding of environmental health sciences with the reality of policy application;and 4. To serve as a technical and educational resource to the region, the nation, and to international agencies in the area of environmental health.